It is generally desirable to know the power output of a gas turbine engine. It is known that such power output can be determined by measuring the torque developed by a shaft extending through the engine on which the various components of the engine, such as, for example, the compressor blades and turbine blades, are mounted. Torque can be determined by measuring the twist or angular deflection of the engine shaft between an air inlet or forward end of the engine and an exhaust end. In the past, it has been known to attach shaft angular position sensors to each end of the shaft and to measure the twist or angular deflection of the torque using these assemblies. The shaft position sensors are generally expensive and have become increasingly more difficult to utilize as the size of gas turbine engines has increased. It is therefore desirable to provide a method and apparatus for determining the torque developed by a gas turbine engine and its corresponding power output without the expense of shaft position sensors.